If you are taking an antibiotic, the medication will cause a mild change in your population of intestinal bacteria that may cause occasional loose stools or mild diarrhea for a few days. These symptoms should stop once your antibiotic treatment ends.
If you have a more dramatic change in your bowel bacteria, and C. difficile bacteria begin to overgrow, your symptoms can include:
Crampy abdominal pain
Pus or blood in your diarrhea (if your illness progresses to C. difficile colitis)
In some cases, fever and abdominal pain develop several days before diarrhea starts.
Diarrhea caused by the C. difficile toxin usually starts while you are taking an antibiotic, but the diarrhea may be delayed and start a few weeks after you have stopped taking the medication.